This invention relates generally to methods and systems for controlling power distribution systems, and more particularly to such methods and systems for controlling circuit breakers within the power distribution systems.
Power distribution systems typically include access points, for example, switchgear units having a plurality of circuit breakers for controlling the flow of power through the system and protecting the system, such as, by providing fault protection. Service personnel may need to access these different points to perform maintenance, service, diagnosis, etc. For example, service personnel or operators may need to replace, service and/or perform maintenance on components of the switchgear, and more particularly, circuit breakers of the switchgear. Occasionally, this work is performed on energized equipment due to necessity. The potential energy of typical switchgear is such that in the event of an fault an arch flash will occur resulting in damage to equipment and/or serious harm or death to service personnel can occur.
In order to ensure that power is provided continuously, except to faulted branch(s), circuit breaker delays are added throughout the system. These delays in the circuit protection typically must meet minimum standards for safety. However, the more sensitive a circuit breaker, the easier the circuit breaker will be activated (e.g., tripped by a voltage spike), which could result, for example, in the shut down of a facility or manufacturing plant. Thus, there is a tradeoff between selectivity and safety.
In order to increase safety to personnel working on (and around) these systems, while also maintaining power through the system, it is known to provide localized safety measures. For example, it is known to increase fault sensitivity in a breaker near a service personnel or operator. For example, a button on a breaker or a switchgear box may be activated to increase fault sensitivity to one or more circuit breakers in the switchgear. Sensors, such as on the door of the switchgear box, also may be provided and cause a portion of the switchgear to have reduced power when the door is opened. In general, an individual controller is provided with each circuit breaker that allows local control of the circuit breaker. However, the increased fault sensitivity operation may affect other parts of the power system. Essentially, these safety measures are used to protect individuals working on or around the power system and temporarily increase the susceptibility of the system to nuisance and trip certain branch circuits in order to minimize the impact to equipment and personnel in the event of a fault event.
Thus, known methods and systems for providing safety measures may not adequately factor in the effects on other parts of the overall power system. Accordingly, disruption to the system may result. Further, it is not possible to quickly initiate measures in other portions of the system, if needed, to compensate for or monitor the activation of the safety measures.